The distance between City X and City Y was 680 km apart. A lorry travelled at an average speed of 90 km/h from City X to City Y. At the same time, a bus travelled at an average speed of 80 km/h from City Y to City X. How much further did the lorry travel than the bus when the lorry met the bus on the way?
Combined speed of the lorry and the bus
= 90 + 80
= 170 km/h
Time taken for the lorry and the bus to meet
= 680 ÷ 170
= 4 h
Difference in the speed between the lorry and the bus
= 90 - 80
= 10 km/h
Distance that the lorry travelled further than the bus
= 4 x 10
= 40 km
Answer(s): 40 km